The present invention relates to a fuel cell system and a microorganism inhibiting method and, more particularly, to a fuel cell system and a microorganism inhibiting method both of which preclude proliferation of microorganisms present in fluid that is circulated through a fuel cell and its circulation line.
In a case where the fuel cell is employed as a power source, an attempt has heretofore been proposed to circulate coolant water for removing heat produced during production of electric power output. With a view to lowering electric conductivity, it has been a usual practice to use pure water admixed with LLC (Long Life Coolant) for preventing pure water from being iced. With such liquid, especially when pure water is admixed with LLC, this component serves as a nourishing source to cause coolant water to be proliferated with microorganisms during a circulation thereof. This results in clogging of a circulation path, causing undesirable degraded reliability in various component parts. Consequently, there is a need for implementing measures for inhibiting proliferation of the microorganisms present in coolant water. Such a situation is also similarly encountered in a use of moistening water.
Japanese Patent Application Laid-Open Publication No. H9-63612 discloses a water cooling type fuel cell system wherein a sterilizer is located in a coolant water supply unit which includes a collecting path for product water. In particular, coolant water is sterilized with ultraviolet light prior to supply of coolant water to the coolant water circulation system for thereby avoiding proliferation of the microorganisms during circulation thereof.